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Yanmar Engine Identification Help

Use this page to help identify your engine model based on year, horsepower and other data. If you do not find your engine listed here you may contact us at: customerservice@torresenonline.com. We will be adding more information to this page often. Let us know what engine you have and we will make it a priority to get your engine listed.

Understanding YANMAR engine model codes

Most engine model designations are on an engine data plate, on the front or the top of the engine. Some older engines have the data plate on the adapter plate between the engine and the gearbox . Here are some examples of engine model codes and their meanings: YSE8 Y= horizontal cylinder, lying down.
SE = engine model type or block type.
8=8 horsepower
If an engine model does not have the Y in the beginning, the engine has a vertical cylinder or cylinders. The numbers 1, 3, 4, and 6 indicate the number of cylinders. For example, 3GM is a 3 cylinder engine with a GM type block. A 2GM is a 2 cylinder engine with a GM type block, and so on.
A 3GM30 is a 3GM that has a larger bore and therefore develops more horsepower than its predecessor. The 1GM, 2GM and 3HM were also uprated to 1GM10, 2GM20 and 3HM35 respectively, note, the suffix numbers are not the horsepower of the engine.
All of the above engines are either 'raw water' cooled or 'fresh water' cooled. An engine with an enclosed cooling system containing fresh water and coolant, in turn cooled by raw water going through a heat exchanger, is a fresh water cooled engine. On engines that are either 'raw' or 'fresh', below 34hp, the fresh water cooled engine has the letter F in the model designation, i.e. a 3HM35F is a freshwater cooled engine. If the F is absent, it is a 'raw' water cooled engine. The JH, LH, LP, LY, CX and KY family of engines are all freshwater cooled. The letter C indicates the engine has a saildrive attached. A 3GM30FC is a 3 cylinder, freshwater cooled engine from the GM family, with a saildrive attached. A 4JH2-BE model is fitted with a down angle gearbox. An M means the engine was shipped from the factory without a gearbox e.g. 6CXM-ETE The 4JH series was uprated to 4JH2 series, then 4JH, series, each series increasing in bore size and horsepower while reducing emission levels to comply with the Bodenzee Regulations in Europe and the EPA / CARB regulations in the USA. 3JH, and 3JH3 versions are also of this family.
The 4LH and 4LHA series are both 4 cylinder engines with the same long block assembled in Japan, but the 4LHA is finally assembled in the USA with US sourced components, the same also applies to the 6LY and 6LYA engines. The models 3JH and over have a suffix in the model code: -E is a normally aspirated export engine
-TE, is a turbocharged, export model engine, -ETE is extra turbocharged -HTE is highly turbocharged, -DTE is deluxe turbocharged
-UTE is ultra turbocharged, -STE is super turbocharged, etc.
When the code has a Z, e.g., 4LHA-STZE, the engine is an inboard outboard model with a Mercruiser sterndrive or 'Z' drive.

Y Series
These horizontal models lay down in a low profile. The series was updated three times with the YSE being the earliest model, followed by the YSB and then the YSM. Either a 2:1 or 3:1 transmission. The models were sea-water cooled, singe cylinder, heavy duty. This series includes the following engines:

Engine	HP	Years In Production	Comments
YSB12	12	1976 - 1977	B=Between
YSB8	8	1976 - 1977	B=Between
YSE12	12	1974 - 1976	E=Early
YSE8	8	1974 - 1976	E=Early
YSM12	12	1977 - 1980	M=Modern
YSM8	8	1977 - 1980	M=Modern

S Series
Vertical models, updated two times with the SVE engines followed by the SB. Single cylinder, 2:1 or 3:1 transmissions, sea water cooled, heavy duty. This series includes the following engines:

Engine	HP	Years In Production	Comments
SB12	12	1976 - 1980	B=Between
SB8	8	1976 - 1980	B=Between
SVE12	12	1974 - 1976	E=Early
SVE8	8	1974 - 1976	E=Early

QM Series
The QM series was available either sea-water or fresh-water cooled. 2:1 or 3:1 transmissions. A designation of F near the end of the model means it is fresh-water cooled. F=Factory Fresh Water This series includes the following engines:

Engine	HP	Years In Production	Comments
2QM	-	originally only distributed in Japan
2QM15	15	1977 - 1980	2 Cylinder
2QM20	22	1975 - 1980	Engines with serial numbers 0001 - 0030 were prototypes and may require different parts. Engines with serial numbers 80001 - 80930 and 81131 - 81180 were also different from the primary production models and may require different parts. Engines with serial numbers 80931 - 81130 and any serial number higher than 81181 will use standard 2QM20 parts.
2QM20(F)	22	1975 - 1980	2 Cylinder
2QM20(H)	22	1975 - 1980	2 Cylinder
3QM	-	originally only distributed in Japan
3QM30	33	1976 - 1980	3 Cylinder
3QM30(F)	33	1976 - 1980	3 Cylinder
3QM30(H)	33	1976 - 1980	3 Cylinder

GM/HM Series
Introduced in 1980 and 1981 this series was a completely new generation of engines. Lighter, smaller, smoother and quieter than previous engines. An F designation on the model number indicates factory fresh-water cooling. 35 AMP alternators. This series includes the following engines:

Engine	HP	Years In Production	Comments
1GM	7.5	1980 - 1983	Raw
2GM	15	1980 - 1983	Raw
2GMF	15	1980 - 1983	Fresh
3GM	22.5	1980 - 1983	Raw
3GMD	22.5	1980 - 1983	.
3GMF	22.5	1980 - 1983	Fresh
3HM	30	1980 - 1983	Raw
3HMF	30	1980 - 1983	Fresh

GM/HM Bored Up Series
Similar to the earlier standard GM/HM series, these engines provide upgraded horsepower and a 55 AMP alternator (1GM10 35 AMP). Special Note: If your engine serial number starts with an 'E' you must make sure that you use parts for the YEU engines. For example, if you have a 2GM20 with a serial number starting with E you actually have a 2GM20YEU. The (YEU) engines are European manufactured and now more common in the United States than the Japan built models. This series includes the following engines:

Engine	HP	Years In Production	Comments
1GM10	9	1983 - 2009	Raw Water
2GM20	18	1983 - December 2005	Raw
2GM20-YEU	18	1997 - Present
2GM20F	18	1983 - December 2005	Fresh
2GM20FYEU	18	-	.
3GM30	27	1983 - December 2005	Raw
3GM30-YEU	27	1997 - Present
3GM30F	27	1983 - December 2005	Fresh
3GM30F YEU	27	-
3HM35	34	1983 - 1992	Replaced with 3JH2
3HM35F	34	1983 - 1992	Replaced with 3JH2

YM Series
Completely redesigned cylinder block and new combustion system. Indirect injection, fresh water cooled with heat exchanger, this new engine line complies with ETA Tier 2 and BSO Tier 2. Electric stop solenoid is standard. This series includes the following engines:

Engine	HP	Years In Production	Comments
2YM15	14	Fall 2004 - Present	US Built
3YM20	22	Summer 2004 - Present	US Built
3YM30	30	Summer 2004 - Present	US Built

JH Series
Extremely smooth running. Two transmission possibilities were available – either a Hurth or 7 degree down angle B type. 80% of the parts for this series of engine are inter-changable since all four engines in the series used the same block. This series includes the following engines:

Engine	HP	Years In Production	Comments
4JH-DTE	77	1985 - 1989	Turbo Charged
4JH-E	44	1983 - 1989
4JH-TE	55	1983 - 1989	Turbo Charged
4JH-THE	66	1985 - 1989	Turbo Charged

JH2 Series
Extremely smooth running. Horsepower upgrade over the previous JH series. Quiter and cleaner exhaust. A B designation on these engines indicate a down angle transmission. This series includes the following engines:

Engine	HP	Years In Production	Comments
3JH(B)E	38	1992 - 1999
3JH2-T(B)E	47	1991 - 1999	Turbo
4JH2-(B)E	51	1989 - 1999
4JH2-DT(B)E	88	1989 - 1999	Turbo-Intercooled
4JH2-HT(B)E	76	1989 - 1999	Turbo-Intercooled
4JH2-T(B)E	63	1989 - 1999	Turbo-Intercooled
4JH2-UT(B)E	100	1991 - 1999	Turbo-Intercooled

JH3 Series
Upgraded blocks, smaller overall size, smoother and quieter. Meets all new EPA requirements. This series is a replacement of the JH2 series. This series includes the following engines:

Engine	HP	Years In Production	Comments
3JH3	40	May 1999 - 2004
4JH3-DTBE	125	Summer 1999 - December 2006	Turbo-Intercooled
4JH3-HTBE	100	Summer 1999 - December 2006	Turbo-Intercooled
4JH3-T(B)E	75	Summer 1999 - December 2006	Turbo
4JH3E	56	May 1999 - 2004

JH4 Series
Redesigned cylinder block and new combustion system. Produces 25% more torque with only a 10% increase in displacement. Lower running speed and less vibration reduce noise by five decibels. Complies with EPA Tier 2 emmissions. This series includes the following engines:

Engine	HP	Years In Production	Comments
3JH4E	39	Summer 2004 - Present
3JH4E	40	Summer 2004 - Present
4JH4E	55	Summer 2004 - December 2006

LH Series
Extremely compact and lightweight. Very powerful. Transmission is a 7 degree down angle (bi-rotational). Also designed to cleanly replace gas V-8 engines. Larger Hp models. A=Built in USA. Available as both inboard and Mercruiser Stern Drive packages. This series includes the following engines:

Engine	HP	Years In Production	Comments
4LH-DTE	170	1990 - 2000	Replaces 350 GM
4LH-HTE	140	1988 - 2000	Turbo-Intercooled
4LH-STE	230	September 1995 - August 1998	Replaces 454 GM
4LH-TE	110	1988 - 2000	Turbo
4LHA-DTE	190	June 2000 - August 2001	Upgrade from 170
4LHA-DTZE	190	Spring 2000 - August 2001	Merc I/O Package
4LHA-HTE	150	Spring 2000 - August 2001	Turbo-Intercooled
4LHA-HTZE	150	Spring 2000 - August 2001	Merc I/O Bravo
4LHA-STE	230	September 1998 - August 2001	Waste gated and US built
4LHA-STZE	230	August 1999 - August 2001	Merc I/O Bravo

LY Series
Introduced in 1992, this is the six cylinder version of the 4LH series. Lightweight, compact with excellent horsepower to weight ration. All models are the same size and weight. Smallest HP in its class.

Race-proven performance with startling power-to-weight capability and low-slung configuration. Extremely popular for repowering petrol-driven engines because of the flat-top, narrow profile of these diesels. The engines benefit further from outstanding fuel economy. This series includes the following engines:

Engine	HP	Years In Production	Comments
6LY-STE	350(70)	1994 - 1996	Turbo-Intercooled
6LY-UTE	315	1992 - 1996	Turbo-Intercooled
6LY2-STE	420	1998 - Present
6LY2A-STE	420	March 2001 - September 2001	US built
6LYA-STE	350	January 1997 - May 2001	US built
6LYA-STP	-
6LYA-UTE	315	January 1997 - December 2001	US built

LP Series
New mini-6 cylinder, super quiet, lightweight, designed for inboard and Merc sterndrive packages. Higher speed (3800 RPM). Many changes from Yanmar's traditional marine models. This series includes the following engines:

Engine	HP	Years In Production	Comments
6LP	250-300	1997 - present
6LP-DTZE	250	January 1998 - September 2001	Merc I/O Package
6LP-STE	300	June 1997 - July 2001	Inboard
6LP-STZE	300	January 1998 - October 2001	Merc I/O Bravo
6LPA-DTE	250	March 2001 - July 2001	US built
6LPA-DTP	260	August 2001 - December 2006	Higher Hp
6LPA-DTZE	250	March 2001 - July 2001	US built
6LPA-STE	300	March 2001 - June 2001	US built
6LPA-STZE	300	March 2001 - June 2001	US built
6LPDTE	250	June 1997 - September 2001	Super Quiet/Inboard

CX Series
Heavy duty, super smooth and quietest in this HP class. Commercial model with 4 valves per cylinder. Premium quality. This series includes the following engines:

Engine	HP	Years In Production	Comments
6CX(M)-ETE	420	1992 - December 2001	Turbo-Intercooled
6CX-GTE	465	Fall 1999 - December 2005	Turbo-Intercooled
6CXM-GTE2	500	July 2001 - Present	Turbo-Intercooled

The Yanmar 2GM20 is a series of inboard marine diesel engine manufactured by the Japanese company Yanmar Co. Ltd.. It is used in a wide range of sailboats and motorboats. The 2GM20 is out of production and has been superseded by the newer Yanmar 2YM20 series.

Specifications[edit]

It is a four-stroke, vertical, water-cooled diesel engine. It is built around two cylinders (hence the '2' in 2GM20) of 75 mm in diameter and 72 mm in stroke, adding up to 0.635 litres in displacement: each cylinder is roughly the size and volume of a 300 ml soft-drink can. The compression system uses a proprietary swirl-type pre-combustion chamber.^[1]

The continuous rating output at the crankshaft is 11.8 kW, at 3400 revolutions per minute (rpm). The maximum output at the crankshaft is 13.4 kW, at 3600 rpm.^[1]

The engine delivers roughly 16 horsepower, for a weight of about 114 kg.

The engine is equipped with a starting motor (D.C. 12V, 1 kW), and an alternator to provide electricity and charge onboard batteries (12V, 55A).

The engine is typically activated by a key and a starting motor switch. Upon turning the key and pressing the starting motor switch, the oil pressure alarm will ring for about a second until the engine starts to run. The exit of cooling water from the exhaust into the sea (typically at the aft of the boat) should be checked at that time. After a few minutes, the hot cooling water alarm will sound if the cooling water does not get through the engine (as when the seawater cock has remained closed -most likely case- or if something is clogging the seawater tubing).

Water pump[edit]

The 2GM20 series uses either a direct seawatercooling system, or an indirect freshwater cooling system (specified by the suffix letter F i.e. 2GM20F). Seawater is pumped into the engine through a seawater pump (impeller type). In the engines equipped with a direct seawater cooling system, seawater is used to cool the internals of the engine directly. The engines equipped with a fresh water cooling system have an additional heat exchanger, where heat transfer occurs between the seawater and internal freshwater.

The impeller of the seawater pump can suffer from wear and tear, especially when run dry for some period of time, in which case it has to be replaced to avoid loss in the flow of cooling seawater, a potential source of engine overheating.

A particularly difficult problem in tropical waters is jellyfish. Their tentacles can be sucked into water intakes. In extremes, it is possible for the rubber exhaust hose to catch fire, the plastic silencer to melt and the head-gasket to fail. In colder waters, boats are far less likely to meet such problems. The solution is to have a large basket-type water strainer and overheat alarms (standard on most Yanmar engines)

The seawater pump is rotated by a short belt linked to the crankshaft.

Fuel filter[edit]

An inline fuel filter is easily accessible from the front part of the engine. The filter retains solid particles and separates water from diesel (as water is heavier than diesel, it will settle at the bottom of the filter), just before the diesel fuel enters the highly sensitive high-pressure fuel pump. The water inside diesel fuel can lead to rusting of the internals of the engine, as well as lubrication problems. The filter element is made of fluted paper with metal end caps.

When the engine has to be bled because air has penetrated into the pipes (usually after running out of diesel), it will usually be necessary to bleed the diesel filter: the top vent is unscrewed so as to let the excess air escape, while diesel fuel is pumped into the fuel filter with the manual fuel lift pump (just behind the yellow dipstick). The vent can be screwed shut when diesel fuel starts to gush out of it.

A primary fuel filter is usually installed upstream of the engine, so as to filter out the larger particles and filter a larger quantity of water that might be present in the fuel.

Every time a filter is disassembled or changed, it will be necessary to bleed it so as to remove excess air, again by opening the top vent so as to let diesel chase all the air (diesel fills up the filter either through gravity -usually the case for the primary filter- or with the help of the fuel lift pump -usually the case for the engine fuel filter-) and diesel starts to gush out. The vent should then be screwed shut.

New models[edit]

The 2GM20 and 3GM30 (three-cylinder) series have now been superseded in the Yanmar catalog by the new lightweight and modernized engines, the 2YM15, 3YM20, and 3YM30. These new engines also feature simplified maintenance of the seawater pump and other services points, as they are now located on the front part of the engine.^[2] These new engines also meet new Tier II emission standards introduced in the EU and the US in 2006.^[3]

Parts[edit]

• Yanmar 2GM20 injectors.

• Yanmar 2GM20 high pressure fuel pump.

• Yanmar 2GM20 oil filter.

• Yanmar 2GM20 dipstick (yellow) and fuel lift pump (top).

• Yanmar 2GM20 cooling seawater cock (in closed position).

Applications[edit]

Versions[edit]

• Yanmar 2GM20: Marine main engine (for export), seawater cooling, model codes: 128271 (S, N, G).
• Yanmar 2GM20-B: Marine main engine (domestic use), seawater cooling, model codes: 128271 (A, B, C).
• Yanmar 2GM20C: Saildrive engine, seawater cooling, model code: 128271 E.
• Yanmar 2GM20F: Marine main engine (for export), freshwater cooling, model codes: 128291 (S, N, G) Pdf.
• Yanmar 2GM20FC: Saildrive engine, freshwater cooling.
• Yanmar 2GM20FV: Marine main engine, freshwater cooling, equipped with compact V-drive marine gear KM3V.Pdf
• Yanmar 2GM20FVE

Notes[edit]

1. ^ ^abYanmar technical reference sheet
2. ^Yanmar website
3. ^Yanmar technical data for the 2YM15, 3YM20 and 3YM30

References[edit]

• Yanmar technical reference sheet [1]
• Yanmar brochure Pdf
• Yanmar Diesel Engine Parts Catalog (1995) 000Y00F5052

Yanmar Gm Series Manual User

External links[edit]

Wikimedia Commons has media related to Yanmar 2GM20 engine.

Yanmar Service Manuals Online

• Yanmar Internet site Yanmar GM series
• Online parts catalogue for the Yanmar 2GM20 series [2]